&nbsp369 &nbspFXUS07 KWBC 312000 &nbspPMD30D &nbspPROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK &nbspNWS CLIMATE PREDICTION CENTER COLLEGE PARK MD &nbsp300 PM EST WED JAN 31 2018 &nbsp &nbsp30-DAY OUTLOOK DISCUSSION FOR FEBRUARY 2018 &nbsp &nbspTHE MONTHLY UPDATE TO THE FEBRUARY 2018 OUTLOOK IS BASED PRIMARILY ON THE &nbspLATEST DYNAMICAL MODEL GUIDANCE FOR THE MONTH FROM THE NCEP CLIMATE FORECAST &nbspSYSTEM (CFS), WEATHER FORECASTS FOR THE FIRST WEEK OF FEBRUARY, AS WELL AS &nbspTEMPERATURE AND PRECIPITATION GUIDANCE FOR THE OUTLOOKS FOR WEEK 2 AND FOR THE &nbspWEEK 3-4 PERIOD. THE MADDEN-JULIAN OSCILLATION OR MJO HAS BEEN ACTIVE RECENTLY &nbspWITH ENHANCED CONVECTION CURRENTLY MOVING FROM THE MARITIME CONTINENT INTO THE &nbspWESTERN PACIFIC. DYNAMICAL MODEL FORECASTS INDICATE THAT THE ENHANCED &nbspCONVECTIVE PHASE OF THE MJO IS LIKELY TO PROPAGATE ACROSS THE WESTERN PACIFIC &nbspIN THE FIRST COUPLE WEEKS OF FEBRUARY. LA NINA CONDITIONS CONTINUE IN LATE &nbspJANUARY, WITH NEGATIVE SEA SURFACE TEMPERATURE (SST) ANOMALIES OBSERVED ACROSS &nbspTHE CENTRAL AND EASTERN PACIFIC OCEAN FROM NEAR THE DATE LINE TO THE COAST OF &nbspSOUTH AMERICA. THE COUPLED ATMOSPHERIC RESPONSE TO LA NINA WAS OBSERVED AS &nbspWELL, WITH POSITIVE OUTGOING LONGWAVE RADIATION (OLR) ANOMALIES DUE TO REDUCED &nbspCONVECTION NEAR THE DATE LINE AND NEGATIVE OLR ANOMALIES DUE TO ENHANCED &nbspCONVECTION OVER THE MARITIME CONTINENT. ENHANCED EASTERLIES WERE OBSERVED OVER &nbspTHE WESTERN AND CENTRAL TROPICAL PACIFIC OCEAN. &nbsp &nbspBASED ON RECENT DYNAMICAL MODEL GUIDANCE, A STRONG RIDGE IS EXPECTED TO DEVELOP &nbspOVER WESTERN NORTH AMERICA DURING THE FIRST TWO WEEKS OF THE MONTH. A TROUGH IS &nbspPREDICTED DOWNSTREAM OF THIS RIDGE OVER CENTRAL NORTH AMERICA IN GUIDANCE FOR &nbspTHE OUTLOOK FOR WEEKS 1 AND 2. THIS CIRCULATION PATTERN IS PREDICTED TO BRING &nbspBELOW NORMAL TEMPERATURES FOR THE NORTHERN CENTRAL CONUS AND MUCH OF THE &nbspEASTERN CONUS FROM THE CENTRAL MISSISSIPPI VALLEY, ACROSS THE OHIO VALLEY TO &nbspTHE CHESAPEAKE BAY, AS WELL AS ACROSS THE GREAT LAKES REGION AND INTO THE &nbspNORTHEAST. FORECASTS FOR THE FIRST HALF OF FEBRUARY LEAD TO INCREASED &nbspPROBABILITIES OF BELOW NORMAL AVERAGE TEMPERATURES FOR THE MONTH, WITH THE &nbspGREATEST PROBABILITIES OVER PARTS OF THE NORTHERN PLAINS/UPPER MISSISSIPPI &nbspVALLEY, WHERE TEMPERATURES ARE PREDICTED TO BE MUCH BELOW NORMAL IN THE FIRST &nbspWEEK OF THE MONTH. ABOVE NORMAL TEMPERATURES ARE LIKELY FOR MOST OF THE WEST, &nbspWHERE A RIDGE AND ABOVE AVERAGE 500-HPA HEIGHTS ARE PREDICTED TO PERSIST &nbspTHROUGH MOST OF THE MONTH, INCLUDING GUIDANCE FROM NCEP GEFS, CFS AND ECMWF &nbspMODELS. ABOVE NORMAL TEMPERATURES CONTINUE TO BE MOST LIKELY FOR THE GULF COAST &nbspREGION AND SOUTHEAST, HOWEVER PROBABILITIES HAVE BEEN REDUCED IN THE MONTHLY &nbspUPDATE DUE TO THE INCREASED PROBABILITIES OF BELOW NORMAL EARLY IN THE MONTH. &nbspDYNAMICAL MODELS INDICATE BELOW NORMAL TEMPERATURES ARE MOST LIKELY OVER &nbspSOUTHEASTERN ALASKA DURING THE FIRST WEEK OF FEBRUARY, HOWEVER BY WEEK 2 &nbspTEMPERATURES ARE PREDICTED TO BE ABOVE NORMAL IN THIS REGION. THE GREATER SKILL &nbspOF FORECASTS FOR SHORTER LEAD TIMES LEADS TO INCREASED PROBABILITIES FOR BELOW &nbspNORMAL AVERAGE TEMPERATURES FOR THE MONTH OVER SOUTHEASTERN ALASKA AND THE &nbspALASKA PANHANDLE. ABOVE NORMAL TEMPERATURES CONTINUE TO BE MOST LIKELY FOR &nbspWESTERN AND NORTHERN ALASKA FOR THE MONTH OF FEBRUARY AS INDICATED BY MODEL &nbspGUIDANCE FROM THE CFS. &nbsp &nbspTHE UPDATE TO THE FEBRUARY PRECIPITATION OUTLOOK INDICATES CHANGES RELATED TO &nbspDYNAMICAL MODEL GUIDANCE, WHERE GREATER WEIGHT IS GIVEN TO FORECASTS FOR THE &nbspFIRST TWO WEEKS, GIVEN THE DROP IN SKILL OF PRECIPITATION FORECASTS WITH &nbspGREATER LEAD TIME. ABOVE MEDIAN PRECIPITATION IS MOST LIKELY FOR MUCH OF THE &nbspEASTERN CONUS DURING THE FIRST WEEK OF THE MONTH, FROM THE CENTRAL GULF COAST &nbspTO THE NORTHEAST. BELOW MEDIAN PRECIPITATION IS MOST LIKELY FOR MUCH OF THE &nbspWESTERN CONUS AND SOUTHERN PLAINS DURING THE EARLY PART OF THE MONTH. THESE &nbspFORECASTS FOR THE FIRST HALF OF THE MONTH ARE BLENDED WITH THE HALF-MONTH LEAD &nbspPRECIPITATION OUTLOOK, WHICH INDICATES THE AVERAGE IMPACTS OF LA NINA FOR &nbspFEBRUARY. THE UPDATE TO THE FEBRUARY PRECIPITATION OUTLOOK INDICATES INCREASED &nbspPROBABILITIES OF BELOW MEDIAN PRECIPITATION FOR MUCH OF THE WEST, FROM SOUTHERN &nbspOREGON ACROSS NEVADA INTO THE SOUTHWEST, AS INDICATED BY RECENT MODEL GUIDANCE. &nbspPROBABILITIES FOR BELOW MEDIAN PRECIPITATION FOR THE SOUTHEAST HAVE DECREASED &nbspFROM THE PRIOR OUTLOOK, WITH ABOVE MEDIAN PRECIPITATION MORE LIKELY EARLY IN &nbspTHE MONTH. PROBABILITIES OF ABOVE MEDIAN PRECIPITATION ARE INCREASED FOR THE &nbspNORTHERN PLAINS FROM EASTERN MONTANA TO MINNESOTA, AND REDUCED FOR AREAS OF THE &nbspNORTHERN ROCKIES, FOLLOWING MODEL FORECASTS FOR WEEKS 1 AND 2. INCREASED &nbspPROBABILITIES FOR ABOVE MEDIAN PRECIPITATION CONTINUE FOR THE NORTHEAST, &nbspEXTENDING FURTHER SOUTH ALONG THE ATLANTIC COAST. THE FEBRUARY PRECIPITATION &nbspOUTLOOK FOR ALASKA IS SIMILAR TO THE HALF-MONTH LEAD OUTLOOK, WITH AN INCREASE &nbspIN THE PROBABILITIES OF ABOVE MEDIAN PRECIPITATION FOR THE ALASKA PANHANDLE. &nbsp &nbspTHE PRIOR FORECAST DISCUSSION FOR THE HALF-MONTH LEAD FEBRUARY OUTLOOK ISSUED &nbspJANUARY 18 IS BELOW. &nbsp &nbsp_____ &nbsp &nbspLA NINA CONDITIONS CONTINUED INTO MID-JANUARY, WITH NEGATIVE SEA SURFACE &nbspTEMPERATURE (SST) ANOMALIES OBSERVED ACROSS THE CENTRAL AND EASTERN PACIFIC &nbspOCEAN FROM NEAR THE DATE LINE TO THE COAST OF SOUTH AMERICA. THE COUPLED &nbspATMOSPHERIC RESPONSE TO LA NINA WAS OBSERVED AS WELL, WITH POSITIVE OUTGOING &nbspLONGWAVE RADIATION (OLR) ANOMALIES DUE TO REDUCED CONVECTION NEAR THE DATE LINE &nbspAND NEGATIVE OLR ANOMALIES DUE TO ENHANCED CONVECTION OVER PARTS OF THE &nbspMARITIME CONTINENT. THE LOW-LEVEL EASTERLIES OBSERVED AT THE 850-HPA LEVEL WERE &nbspENHANCED OVER THE WESTERN PACIFIC. LA NINA IS EXPECTED TO IMPACT THE &nbspTEMPERATURE AND PRECIPITATION PATTERNS IN FEBRUARY OVER NORTH AMERICA. TROPICAL &nbspCONDITIONS PROJECT ONTO THE MADDEN-JULIAN OSCILLATION (MJO) PHASE 4, WITH &nbspENHANCED CONVECTION OVER THE MARITIME CONTINENT. DYNAMICAL MODELS PREDICT &nbspPROPAGATION OF THE ACTIVE MJO INTO THE WESTERN PACIFIC IN EARLY FEBRUARY. A &nbspPREDICTED ACTIVE MJO, WITH THE ONGOING LA NINA BASE STATE, COULD IMPACT CLIMATE &nbspVARIABILITY IN FEBRUARY, INCREASING THE UNCERTAINTY IN THE AVERAGE FEBRUARY &nbspFORECAST. THE CURRENT MJO PHASE AND FORECAST INCREASE THE LIKELIHOOD OF ABOVE &nbspNORMAL TEMPERATURES OVER THE EASTERN CONUS AND BELOW NORMAL TEMPERATURES IN THE &nbspNORTHWEST EARLY IN THE MONTH. &nbsp &nbspTHE FEBRUARY TEMPERATURE OUTLOOK RELIES PRIMARILY ON CALIBRATED PROBABILITIES &nbspOF ABOVE AND BELOW NORMAL TEMPERATURES FROM THE NORTH AMERICAN MULTI-MODEL &nbspENSEMBLE (NMME), WITH CONSIDERATION OF THE IMPACTS OF AN ONGOING LA NINA, AS &nbspEXPRESSED THROUGH BRIDGING OF PREDICTED NINO 3.4 REGION SST ANOMALIES AND &nbspCALIBRATED TEMPERATURE PROBABILITIES, USING STATISTICAL FORECASTS OF ENSO &nbspIMPACTS. ADDITIONAL CONSIDERATION WAS GIVEN TO DYNAMICAL MODEL FORECASTS FOR &nbspTHE BEGINNING OF FEBRUARY THAT ARE IMPACTED BY AN ACTIVE MJO. &nbsp &nbspTHE FEBRUARY TEMPERATURE OUTLOOK INDICATES INCREASES IN THE PROBABILITIES OF &nbspABOVE NORMAL TEMPERATURES FOR THE U.S. SOUTHWEST, NORTHWARD TO SOUTHERN &nbspWYOMING. INCREASED PROBABILITIES OF ABOVE NORMAL TEMPERATURES EXTEND EASTWARD &nbspTO THE SOUTHERN GREAT PLAINS, THE GULF COAST, AND THE SOUTHEAST REGION, AND &nbspEXTEND NORTHWARD ALONG THE EAST COAST TO NEW ENGLAND. PROBABILITIES ARE HIGHEST &nbspFOR PARTS OF THE SOUTHWEST AND SOUTHERN TEXAS AND LOUISIANA, CONSISTENT WITH &nbspDECADAL TEMPERATURE TRENDS AND LA NINA IMPACTS. THE LIKELIHOOD OF ABOVE NORMAL &nbspTEMPERATURES ARE REDUCED OVER NEW ENGLAND AND EQUAL CHANCES IS INDICATED OVER &nbspTHE MIDWEST, AS WELL AS MUCH OF SOUTHERN CALIFORNIA AND NEVADA, WHERE &nbspVARIABILITY RELATED TO MJO AND LA NINA INCREASE UNCERTAINTY IN THE NMME &nbspPREDICTED FEBRUARY MEAN TEMPERATURES. BELOW NORMAL TEMPERATURES ARE MOST LIKELY &nbspFOR SOUTHEASTERN REGIONS OF ALASKA AND PARTS OF THE PACIFIC NORTHWEST, FROM &nbspNORTHERN CALIFORNIA INTO OREGON AND WASHINGTON, AND EASTWARD INTO MONTANA, &nbspASSOCIATED WITH PREDICTED TEMPERATURE PROBABILITIES FOR EARLY FEBRUARY &nbspRESULTING LARGELY FROM THE COMBINED IMPACTS OF LA NINA AND THE MJO. ABOVE &nbspNORMAL TEMPERATURES ARE MOST LIKELY FOR WESTERN AND NORTHERN ALASKA, AS &nbspINDICATED BY NMME DYNAMICAL MODEL FORECASTS AND DECADAL TRENDS. &nbsp &nbspTHE FEBRUARY PRECIPITATION OUTLOOK, RELYING PRIMARILY ON THE &nbspPROBABILITY-ANOMALY-CORRELATION CALIBRATED PROBABILITIES FROM THE NMME, &nbspRESEMBLES THE CANONICAL IMPACTS DUE TO LA NINA, WITH GREATER UNCERTAINTY &nbspRELATED TO ADDITIONAL CLIMATE FORCING SUCH AS THE MJO. ABOVE NORMAL &nbspPRECIPITATION IS MOST LIKELY FOR PARTS OF THE NORTHERN ROCKY MOUNTAINS, FROM &nbspNORTHERN UTAH INTO EASTERN OREGON AND WASHINGTON, AS WELL AS IDAHO, MONTANA AND &nbspWESTERN WYOMING. MONTHLY AVERAGE PRECIPITATION IS MOST LIKELY TO BE ABOVE &nbspNORMAL FOR THE MIDWEST FROM THE CENTRAL AND UPPER MISSISSIPPI VALLEY INTO THE &nbspOHIO VALLEY AND GREAT LAKES REGION. ABOVE NORMAL PRECIPITATION IS ALSO MOST &nbspLIKELY TO THE EAST IN NEW ENGLAND, HOWEVER WITH GREATER UNCERTAINTY. BELOW &nbspNORMAL PRECIPITATION IS MOST LIKELY ACROSS THE SOUTHERN CONUS FROM NEW MEXICO &nbspACROSS TEXAS AND THE GULF COAST TO THE SOUTHERN ATLANTIC COAST, FOLLOWING &nbspCANONICAL IMPACTS OF LA NINA AS PREDICTED BY CALIBRATED PROBABILITY FORECASTS &nbspFROM THE NMME. EQUAL CHANCES OF ABOVE, NEAR OR BELOW NORMAL PRECIPITATION IS &nbspINDICATED FOR THE WEST COAST OF THE CONUS AND WESTERN AREAS OF THE SOUTHWEST, &nbspWHERE UNCERTAINTY IS GREATER DUE TO VARIABILITY IN DYNAMICAL MODEL FORECASTS. &nbspTHE INCREASED LIKELIHOOD OF BELOW NORMAL PRECIPITATION INDICATED FOR &nbspSOUTHEASTERN ALASKA INCLUDING THE PANHANDLE IS A CANONICAL IMPACT OF AN ONGOING &nbspLA NINA. ABOVE NORMAL PRECIPITATION IS MOST LIKELY FOR WESTERN AND NORTHERN &nbspALASKA, AS INDICATED BY NMME FORECAST PROBABILITIES. &nbsp &nbspFORECASTER: DAN COLLINS &nbsp &nbspTHE CLIMATIC NORMALS ARE BASED ON CONDITIONS BETWEEN 1981 AND 2010, FOLLOWING &nbspTHE WORLD METEOROLOGICAL ORGANIZATION CONVENTION OF USING THE MOST RECENT 3 &nbspCOMPLETE DECADES AS THE CLIMATE REFERENCE PERIOD. THE PROBABILITY ANOMALIES &nbspFOR TEMPERATURE AND PRECIPITATION BASED ON THESE NEW NORMALS BETTER REPRESENT &nbspSHORTER TERM CLIMATIC ANOMALIES THAN THE FORECASTS BASED ON OLDER NORMALS. &nbsp &nbspTHE NEXT MONTHLY OUTLOOK...FOR MAR ... WILL BE ISSUED ON THU FEB 15 2018 &nbsp &nbspTHESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1981-2010 BASE PERIOD. &nbsp &nbsp